I have a scratch on my Helmke Viotti violin and when I got my violin, I also received a paper on how to take care of it. It says to use Old English will hide any little nicks or scratches very well? Can I trust it? Exactly what are the steps to do it? What kind of Old English product? Dark wood or light wood?

you should wipe it down every time you finish practicing or playing to avoid buildup of rosin and duct on the body and strings-the same goes for your bow stick.
First wipe the instrument down well with a clean dry soft cloth.

You can clean your fingerboard by first wiping it and the with a cloth just barely dampened with alcohol wipe it down until no more black gunk comes off of it. Clean the strings the same way. Be careful that you don’t drip the alcohol on the varnish!

Use Old English on a cloth and apply in clock wise circles to work into the wood. for any colored wood.